Scaffolds are ubiquitous structures that are employed to support platforms for construction workers during the repair and construction of buildings. The platforms are formed by positioning plural wood planks in side-by-side orientation across horizontal supports that are part of the scaffold framework. There are many types of scaffold frames and the like but a typical framework is fabricated from interconnected lengths of metal tubing. Many different working platforms may be supported by the scaffold structure, at the same or different elevations to provide access to different work sites on a building that is being worked on.
In order to minimize the variability in the structure of scaffolds, and to thus introduce some standardization to the structures, the wood planks that are used in scaffolds are typically standard 2×8 or 2×10 boards. The most typical plank is nominally a 2×10 board that is an engineered LVL (laminated veneer lumber) or solid sawn yellow pine. While different scaffolds use different lengths of planks, the boards are usually either 9, 12 or 16 feet in length. The planks are typically arranges longitudinally in a side-by-side manner on the supporting scaffolding framework headers so that there is a minimum of 6 inches overlap between adjacent planks. The planks are usually not secured together in some manner and in many instances the boards are simply laid side-by-side. As one would guess, this can present a dangerous situation because of the possibility of relative movement between the planks—for instance, gaps opening between planks, or in the case of one board moving when it should be stationary. Despite these known risks, there are no current safety standards that mandate securement of scaffolding planks.
In some instances the side-by-side planks are clamped together. However, prior known scaffold plank clamps apparatus do not fully solve the problems associated with unsecured or inadequately secured planks. One typical practice in the industry is to attach a wooden board across the aligned planks with nails or screws. If the transverse board is attached to the upper surface of the planks, it can cause workers to trip over it. If the board is attached to the lower side of the combined planks there is no tripping risk, but attaching the board to the underside of the planks is not feasible given the difficulty and time required.
There are also examples of mechanical clamps that are designed to stabilize the planks and minimize relative movement. One example is disclosed in U.S. Pat. No. 6,371,245. In that patent, a clamp has a recess into which planks are received with opposed end flanges. An adjustable abutment plate allows the end flanges to be moved toward one another such that the planks are compressed together. The patent describes spikes on the flanges that engage the outer exposed edges of the outermost planks that engage the planks by penetration into the wood. The clamp described in this patent secures the group of clamped planks against relative movement along a horizontal plane.
Despite the known apparatus and methods for clamping scaffold planks, there is a need for a secure, convenient and efficient clamp.
The present invention comprises a clamp that is easily and quickly attached to a scaffold platform that is defined by plural planks laid side-by-side in a scaffold structure. The clamp has upright stops on opposite ends of the clamp that engage the outermost planks in the platform. The clamp is defined by an elongate bar that is longitudinally adjustable, both in a large scale sense and in a smaller scale sense.
The clamp is installed and resides beneath the planks and is therefore not a trip-hazard for workers, and the clamp is readily adjustable to compress the planks to one another to stabilize the platform. The invention creates a stronger and more stable platform by eliminating the vertical deflection of each individual plank as well as any other relative movement. The inventive clamp features adjustable telescopic tubing which allows for the user to adjust the clamp to be utilized on a number of different scaffolding frame widths. The widths that are typical are 3′, 3.5′, 4′ and 5′ wide. Finer adjustments to the width of the clamp are made available through a threaded clamping nut that can only be adjusted using a ⅞ socket, which is a size typically carried by a scaffolding worker. This reduces the likelihood of tampering of the apparatus by the lay person.
The invention further comprises guard post support members that may be attached to the clamp and to which a vertical post may be attached. Horizontal rails may be attached to adjacent guard post supports to construct a secure safety rail system.